However, as part of the larger PhD study (Tomlin 2014), item-total correlations were performed, and items with weak item-total correlations (r < 0.3) were removed.
The EFA found four items (5, 11, 15, 16) with weak item-total correlations (below 0.20) and these items were dropped to create 16-item scoring of the scale.
Initially, the test consisted of 12 items, but one item was deleted due to weak item total correlation (0.29).
Item 49 ("Many people are very "fake" and do not behave the way they really are") showed a weak item total correlation with rit = .11 in the subscale-referred analysis and rit = .18 in the scale-referred analysis in the school sample, implying that this item has too little in common with the variance of the whole scale and the other items.
At the item level, item 2, "In this clinical area, it is difficult to speak up if I perceive a problem with patient care", raised validity concerns: the item-factor loading was below the acceptable threshold of 0.03, and the subscale-corrected item-total correlation indicated a weak relationship with the other items in the scale, thus impairing discriminative ability.
Criterion validity for item-total correlation with Pearson correlation test (weak < 0.30; moderate 0.31 – 0.60; strong 0.61 – 0.9; very strong 0.91 -1.0) [ 8].
The item-total correlation for the PSS was largely strong, with relatively weak correlation for Item 4 (r =.39, p <.01) and Item 12 (r =.27, p <.01), and the other items ranging from r =.53 (p <.01) to r =.74 (p <.01).
This is supported when an item's corrected item-total correlation is ≥0.40 with the dimension it is hypothesised to belong to, while correlating weaker with all other dimensions [ 19, 20].
The content validity index for all items could reach 1. Corrected item-total correlation scores were ≥0.4 for four symptom questions (feeling of incomplete bladder emptying, intermittency, weak stream and straining).
Item-total correlation coefficients ranged from.51 to.76.
Content validity, item reliability (test retest, item-total correlation, item difficulty) and test reliability (internal consistency) were established.
